The Application of Dielectric Retrieval Algorithms for Mapping Soil Salinity in a Tropical Coastal Environment Using Airborne Polarimetric SAR

The Alligator River Region of the Northern Territory, Australia, is identified as a region particularly susceptible to saltwater intrusion into systems dominated by freshwater processes. Attempts have been made by the Parks and Wildlife Commission of the NT to restrict the intrusion by creating physical earth barrages. In this study the use of Airborne Polarimetric Synthetic Aperture Radar for mapping soil salinity is examined. Three dielectric retrieval algorithms, the Small Perturbation, Physical Optics, and Dubois models have been implemented, and the results of these were combined to retrieve an improved estimate of the magnitude of the imaginary part of the complex dielectric constant for soil salinity discrimination. An efficient data selection process was employed to allow application of these models in this natural environment. Vegetation correction to the small perturbation and physical optics models before combination with the Dubois model improved classification accuracy in the semivegetated areas.